Gripper shuttle

ABSTRACT

The shuttle housing is provided with a partition between the arms of the gripper clamp to reinforce and stiffen the housing. The partition can be integrally molded with the housing or secured in place by welding or riveting. At least one of the clamp arms is provided with a thickened part to abut the partition when in a clamping position and thereby prevent premature wear of the arms.

United States Patent 1 [111 3,854,506 Pfarrwaller Dec. 17, 1974 GRIPPER SHUTTLE [75] Inventor: Erwin Pfarrwaller, Winterthur, Prlmary Exammer l ,lemy Jaudon Attorney, Agent, or Fzrml(enyon & Kenyon Reilly Switzerland Carr & Chapln [73] Assignee: Sulzer Brothers Ltd., Winterthur,

Switzerland [22] Filed: May 23, 1973 [57] ABSTRACT 21 A l.N 363,151 1 pp 0 The shuttle housing lS provided with a partition between the arms of the gripper clamp to reinforce and Foreign pp n Priority Data stiffen the housing. The partition can be integrally May 26, 1972 Switzerland 7814/72 molded with the housing or secured in place by welding or riveting. At least one of the clamp arms is pro- [52] us. Cl. .4 139/125 vide with a hickened part to abut the partition when [51] Int. Cl. D03j 5/06 in'a lamping position and thereby prevent premature [58] Field of Search 139/122 N, 125, 126, 196 W ar f th arms.

[56] References Cited 10 Claims, 5 Drawing Figures UNITED STATES PATENTS 1712.345 l/l973 Pfarrwnller 139/125 PATEHTEU LLB I 74 sum 2 or 2 1 GRIPPER SHUTTLE This invention relates to a gripper shuttle for picking weft yarns in a weaving machine and particularly in a weaving machine wherein the weft package remains outside a shed.

Gripper shuttles have been known to have a shuttle housing or body in which a gripper clamp is received in order to clamp onto a weft yarn for picking into a shed as well as a nose at one end. Known shuttles of this type generally have standard dimensions of approximately 90 X 14 X 6 millimeters (mm) and weigh approximately 30 to 60 grams (g). The gripper clamp which is U-shaped, usually has two resiliently biased arms which press two clamping jaws against one another and which are interconnected by a yoke at the end distal from the jaws. In order to open the gripper clamp during operation, a wedge-shaped or conical gripper clamp opener is introduced at an appropriate place between the arms of the gripper clamp. When a weft yarn end is introduced between the opened jaws, for instance, by a similar gripper clamp serving as a yarn feeder, and the gripper clamp opener is then withdrawn, the gripper clamp takes over the yarn for the next pick.

As a rule, the nose is a solid metal item, such as steel. As seen in the direction of flight, the nose has a kind of blunt rounded cutting edge at the front to facilitate passage of the shuttle through the teeth which usually form a guide for the shuttle and to facilitate the entry of the shuttle into a shuttle brake on the catching side. The gripper clamp yoke and the nose can, in a known manner, be unitary or can be made of different materi- 'als and interconnected by electronic welding or riveting or in some other way. As a rule, however, the nose is welded to the front end of the shuttle housing or is even a unitary member.

In most of the known gripper shuttles, the housing takes the form of a flat smooth tubular metal member which is substantially rectangular or octagonal in crosssection. The housing is open at a rear end and has slitlike recesses in each of two wide side walls in which the weft feeder enters when the gripper clamp is open so as to introduce a weft yarn end between the expanded jaws in the manner hereinbefore described. Generally, two passages are formed in the wide side walls at a distance of approximately 15 millimeters (mm) from the rear end of the shuttle housing opposite one another through which the gripper clamp opener is introduced between the two arms of the gripper to open the same. The gripper clamp nose portion closes the front end of the tubular member.

The usual procedure for assembly of the shuttle is for the gripper clamp to be introduced, with the yoke at the front, into the shuttle housing from the rear and to be secured to the shuttle housing, and possibly to the nose as well, by welding or riveting or in some other form. In a known construction, the front end of the shuttle housing and the yoke of the gripper clamp are welded together electronically to the nose simultaneously in a single pass.

in another known construction, disclosed in Swiss Patent Specification 466,829, the nose and the gripper clamp are unitary. The shuttle housing has the same external dimensions as in the all-metal constructions described but is made of a light tough plastics, such as polyethylene or tetrafluoroethylene, and is open at the front end. In order to assemble the shuttle, the gripper clamp is introduced into the tubular member from the front until the tubular member abuts an abutment step on the nose, whereafter the shuttle housing is riveted to the gripper clamp yoke. A plastics shuttle of this kind has considerable advantages over the older type of allmetal shuttle. Due to a reduced weight, the speed of shooting, i.e., the speed at which the yarn is picked into the shed, can be increased for a given shooting energy. Also because of the good frictional properties of plastics on steel and other metals, the lubrication of plastics shuttles can be reduced considerably, even if not completely, without risk of the fabric being soiled. Further, there is an appreciable forwards shift, i.e., a shift in the shooting direction, of the center of gravity of the shuttle. This nose heaviness improves the behavior ofthe shuttle in passing through the teeth of the guide.

In modern weaving machines, shooting speeds of up to something like 30 meters/second and picking rates of more than 300 picks/minute are used. The shuttle must therefore be accelerated to full speed, then retarded in the shuttle brake on the catching side, within a few thousandths of a second. Considerable forces are needed for this purpose even though the shuttle is light. Shuttle life, which runs into several million picks, is limited inter alia, disregarding failures associated with breakage of the gripper clamp, by distortions of the shuttle body which occur over the course of time in operation and which may, in the end, prevent the shuttle from moving correctly.

Accordingly, it is an object of the invention to increase the life of gripper shuttles.

It is another object of the invention to increase the resistance of a shuttle to deformation over extended periods of use.

It is another object of the invention to strengthen a shuttle against distortion during use.

Briefly, the invention provides a shuttle made up of a housing and a gripper clamp mounted within the housing with a web-like partition i.e., a stay-like longitudinal partition extending within the housing over at least some of the length of the housing. This partition greatly stiffens and strengthens the shuttle housing to better deal with the stresses occurring in operation, particularly during retardation, without having any disadvantages as compared with the prior art.

In one embodiment where the gripper clamp has two spring arms disposed in opposed relation within the housing, the partition is disposed in a gap between the two arms. In this case, the partition is preferably integrally formed with the shuttle housing.

According to another feature, the shuttle housing is in known manner made of a tough impact-resistant plastics, e.g., polyethylene or tetrafluoroethylene while the gripper clamp and a nose at one end of the clamp are made of steel. In this case, the gripper clamp and the nose can, with advantage, form a single unit. This construction helps to retain all the advantages of the known plastics shuttle while increasing the useful life of the shuttle considerably.

In another embodiment, one or both of the spring 5 arms of the clamp are provided with a thickened part which is located to abut the partition when the arms are in a clamping position. The thickened part serves to positively locate the jaws at the ends of the arms to ensure a constant position of the jaws and, thus, facilitate yarn transfer after opening of the clamp.

These and other objects and advantages of the invention willbecome more apparent from the following detailed description and appended claims taken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a top view, partly sectioned, of a gripper shuttle according to the invention;

FIG. 2 illustrates a view taken on line IIII of FIG.

FIG. 3 illustrates a side view of the shuttle of FIG. 1;

FIG. 4 illustrates a view of the gripper clamp and shuttle nose of the invention in the same position as FIG. 1; and

FIG. 5 illustrates a detail view of a modified shuttle according to the invention.

Referring to FIGS. 1 and 4, a gripper or spring clamp comprises two spring arms 1, 1' which by their spring force press together clamping jaws 2, 2' at their rear free ends so that the jaws 2, 2' can retain a weft yarn end 3 clamped therebetween. The front ends of the arms 1, l are rigidly interconnected by a yoke 4. This yoke 4 is formed with an aperture 5 which, as shown in FIGS. 1 and 2, serves for the rigid securement of the yoke 4 to a shuttle housing 6 at a place 7. A shuttle nose 8 is positioned at the front end of the yoke 5 and can either be integral therewith or connected thereto, e.g., by electron welding or in some other way. The nose 8 has a step or shoulder or the like 9 on which the front end of the shuttle housing 6 bears and with which such housing 6 is flush. This ensures that the complete shuttle has a smooth surface so that the shuttle can move without disturbances and with very little vibration through the teeth of a guide and enter a shuttle brake of a weaving machine (not shown). The nose 8 therefore closes the front end of the housing 6.

Referring to FIGS. 1 and 2, the housing 6 is formed at the rear open end with a slit-like recess 11, 11 in each wide side walI 10, into which a yarn feeder introduces the weft yarn end when the jaws 2, 2 are open to transfer such end to the gripper clamp in the manner hereinbefore described. The walls 10, 10 are formed at some distance from the rear end with two passages 12, 12' through which a wedgeshaped or conical gripper opener (not shown) is introduced to spread the two arms 1, 1' of the spring clamp apart from one another and open the gripper. In the places where the gripper opener contacts the arms 1, 1, there are thickened parts or hard-metal inserts 13, 13' to prevent premature wear of the clamp arms 1, 1. Another pair of thickened parts 14, 14 is disposed on the arms 1, 1' near the recess 11 to cooperate with a gripper opener (not shown) on the catching side of the weaving machine. This latter opener operates after picking.

In order to stiffen and strengthen the shuttle housing 6, a web-like i.e., stay-like longitudinal partition comprising two parts 15, 15a extends inside the housing 6, between the wide side walls l0, 10 disposed on either side of the gripper clamp, over the whole length of the gap between the two sprung arms 1, l'. The partition 15, 15a leaves sufficient clearance on either side to enable the open gripper clamp to be introduced from the front end of the shuttle during assembly thereof without impairing the free movement of the sprung arms 1, 1 in operation. That is, the partition 15, 15a is spaced from each opposed wall of the housing 6 to permit passage of each jaw 2, 2'. Basically, the shuttle housing 6 has the shape of a smooth section tube which can be produced by extrusion or casting (preferably as a pressure casting) or by drawing or in some other way and which can be made of metal or plastics.

The web-like partition 15, 15a can be formed either simultaneously with the tubular member during production of the tube or subsequently, in which case the partition parts 15, 15a can be secured to the walls 10, 10 by screwing or riveting or sticking or welding, provided that the connection is a rigid one. As a rule, extra machining is necessary to ensure a smooth flush transition in the nose portion between the nose surface and the surface of the housing 6. The rear open end of the housing 6 where the picking striker strikes the housing 6 when the shuttle is shot for picking has flangelike thickened parts 16, 16' provided in a known manner to form a partial closure outside the region of the recesses 11, 11 of the rear apertures in the housing 6.

Referring to FIG. 5, the arms 1, 1' have thickened parts 21, 21' which, in the clamping position of the jaws 2, 2 or arms 1, 1 shown in FIG. 5, form abutments for limiting the closing movement of the arms 1, 1'. With such an arrangement, the position of the jaws 2, 2 relative to the housing 6 always remains unchanged even after several millions of picking operations. In addition. the clamping position of the jaws 2, 2 with a yarn 3 clamped in place just before the jaws close together, for example during a yarn catching operation, remains the same. This facilitates yarn transfer, i.e., the introduction of the yarn 3 between the jaws 2, 2', after opening of the spring clamp.

In an alternative form, corresponding thickened parts can be provided on the part instead of on the arms 1, 1'. Also, the thickened parts can be provided in that part of the arms 1, l which is to the right of the passage 12 in FIG. 5, so that the thickened parts cooperate with the wall part 15.

In another embodiment, a single thickened part, for instance, the part 21 on spring arm 1 as shown in FIG. 5, may be sufficient, arm 1 being devoid of a thickened part. Arm 1 must then be more strongly biased, e.g., by corresponding finishing, than arm 1'. With the spring clamp closed, the part 21 is always in engagement with the wall part 15a, so that the jaws 2, 2' are in a constant position.

Alternatively, the arms 1, l of the spring clamp as shown in FIG. 5, may be provided with thickened parts 13, 13' and 14, 14' as shown in FIG. 4, in addition to the thickened part or parts 21, 21'.

What is claimed is:

1. A gripper shuttle for picking weft yarns in a weaving machine comprising a housing, a gripper clamp mounted within said housing having means for gripping a weft yarn, and a stay-like longitudinal partition extending within said housing over at least some of the length of said housing for reinforcing said housing.

2. A gripper shuttle as set forth in claim 1 wherein said clamp has a pair of spring arms for gripping a weft yarn and said partition is disposed between said arms.

3. A gripper shuttle as set forth in claim 1 wherein said partition is integral with said housing.

4. A gripper shuttle as set forth in claim 1 wherein said housing is made of plastic and said clamp is made of steel.

5. A gripper shuttle as set forth in claim 2 wherein at least one of said arms has a thickened part abutting said partition with said arms in a clamping position.

6. A gripper shuttle as set forth in claim 2 wherein one of said arms has a thickened part abutting said partition with said arms in a clamping position and is biased towards the other of said arms under a greater biasing force than said other arm is biased towards said one arm.

7. A gripper shuttle for picking weft yarns in a weaving machine comprising a housing, a gripper clamp mounted in said housing and having a pair of spring biased arms for gripping a weft yarn, and a stay-like longitudinal partition within said housing between said arms for reinforcing said housing.

8. A gripper shuttle as set forth in claim 7 wherein said partition includes two longitudinal spaced parts, at least one of said arms having a thickened part abutting said partition with said arms in clamping position.

9. A gripper shuttle as set forth in claim 7 wherein each arm has a jaw on a free end and said partition is spaced from each opposed wall of said housing to per mit passage of each respective jaw therebetween.

10. A gripper shuttle as set forth in claim 7 wherein said partition is integral with said housing. 

1. A gripper shuttle for picking weft yarns in a weaving machine comprising a housing, a gripper clamp mounted within said housing having means for gripping a weft yarn, and a stay-like longitudinal partition extending within said housing over at least some of the length of said housing for reinforcing said housing.
 2. A gripper shuttle as set forth in claim 1 wherein said clamp has a pair of spring arms for gripping a weft yarn and said partition is disposed between said arms.
 3. A gripper shuttle as set forth in claim 1 wherein said partition is integral with said housing.
 4. A gripper shuttle as set forth in claim 1 wherein said housing is made of plastic and said clamp is made of steel.
 5. A gripper shuttle as set forth in claim 2 wherein at least one of said arms has a thickened part abutting said partition with said arms in a clamping position.
 6. A gripper shuttle as set forth in claim 2 wherein one of said arms has a thickened part abutting said partition with said arms in a clamping position and is biased towards the other of said arms under a greater biasing force than said other arm is biased towards said one arm.
 7. A gripper shuttle for picking weft yarns in a weaving machine comprising a housing, a gripper clamp mounted in said housing and having a pair of spring biased arms for gripping a weft yarn, and a stay-like longitudinal partition within said housing between said arms for reinforcing said housing.
 8. A gripper shuttle as set forth in claim 7 wherein said partition includes two longitudinal spaced parts, at least one of said arms having a thickened part abutting said partition with said arms in clamping position.
 9. A gripper shuttle as set forth in claim 7 wherein each arm has a jaw on a free end and said partition is spaced from each opposed wall of said housing to permit passage of each respective jaw therebetween.
 10. A gripper shuttle as set forth in claim 7 wherein said partition is integral with said housing. 